1. Field of the Invention
The present invention relates generally to a mask and a mask assembly including the same. More particularly, the present invention relates to a mask used for depositing an organic emission layer and a mask assembly having the same.
2. Description of the Related Art
A display device is a device for displaying images, and recently, a display device including an organic light emitting diode (OLED) has become prominent.
Unlike a liquid crystal display (LCD), the OLED has the characteristic of self-emission and does not require a light source so that the thickness and weight of an overall display device can be reduced. The OLED exhibits high quality characteristics such as low power consumption, high luminance, and a high response speed.
In order to manufacture the OLED display, an electrode with a particular pattern, an organic emission layer, and the like must be formed, for which a deposition method using a mask assembly may be employed.
In further detail, the organic light emitting display includes pixels which are a basic unit for displaying images on a substrate, and which are arrayed in a matrix form, and an organic light emitting diode in which an anode, a first electrode, a cathode, and a second electrode are sequentially formed, with organic emission layers each emitting light such as red, green, blue, etc. for each pixel therebetween. Organic materials forming the organic emission layer are very vulnerable to moisture, oxygen, etc. so that they should be thoroughly isolated from moisture during a process of forming the organic emission layer and after forming the organic emission layer. Accordingly, it is difficult to perform patterning using a general photolithography process. Therefore, the organic emission layer is formed using a mask on which a pattern opening part for penetrating deposition materials only through a portion corresponding to each pattern is formed.
Recently, a mask assembly comprising a frame including an opening part and a plurality of masks in a band shape, both ends of which are fixed to the frame, corresponding to the opening part, has been used.
The mask assembly in the related art is fixed to the frame by applying tensile force to the mask, so that the shape of the pattern formed in the mask may be deformed due to tensile force applied to the mask.
The above information disclosed in this Background section is only for enhancement of an understanding of the background of the described technology, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.